1
|
Jang J, Joo S, Yeom J, Jo Y, Zhang J, Hong S, Park CB. Lateral Piezoelectricity of Alzheimer's Aβ Aggregates. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2406678. [PMID: 39159132 DOI: 10.1002/advs.202406678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2024] [Revised: 08/01/2024] [Indexed: 08/21/2024]
Abstract
Alzheimer's disease (AD) is the most frequent neurodegenerative disorder in the elderly aged over 65. The extracellular accumulation of beta-amyloid (Aβ) aggregates in the brain is considered as the major event worsening the AD symptoms, but its underlying reason has remained unclear. Here the piezoelectric characteristics of Aβ aggregates are revealed. The vector piezoresponse force microscopy (PFM) analysis results exhibit that Aβ fibrils have spiraling piezoelectric domains along the length and a lateral piezoelectric constant of 44.1 pC N-1. Also, the continuous sideband Kelvin probe force microscopy (KPFM) images display that the increment of charge-induced surface potential on a single Aβ fibril is allowed to reach above +1700 mV in response to applied forces. These findings shed light on the peculiar mechano-electrical surface properties of pathological Aβ fibrils that exceed those of normal body components.
Collapse
Affiliation(s)
- Jinhyeong Jang
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
- Applied Science Research Institute, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
| | - Soyun Joo
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
| | - Jiwon Yeom
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
| | - Yonghan Jo
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
| | - Jingshu Zhang
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
| | - Seungbum Hong
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
| | - Chan Beum Park
- Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 335 Science Road, Daejeon, 34141, Republic of Korea
| |
Collapse
|
2
|
Katariya RA, Sammeta SS, Kale MB, Kotagale NR, Umekar MJ, Taksande BG. Agmatine as a novel intervention for Alzheimer's disease: Pathological insights and cognitive benefits. Ageing Res Rev 2024; 96:102269. [PMID: 38479477 DOI: 10.1016/j.arr.2024.102269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/01/2024] [Accepted: 03/08/2024] [Indexed: 03/24/2024]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by progressive cognitive decline and a significant societal burden. Despite extensive research and efforts of the multidisciplinary scientific community, to date, there is no cure for this debilitating disease. Moreover, the existing pharmacotherapy for AD only provides symptomatic support and does not modify the course of the illness or halt the disease progression. This is a significant limitation as the underlying pathology of the disease continues to progress leading to the deterioration of cognitive functions over time. In this milieu, there is a growing need for the development of new and more efficacious treatments for AD. Agmatine, a naturally occurring molecule derived from L-arginine, has emerged as a potential therapeutic agent for AD. Besides this, agmatine has been shown to modulate amyloid beta (Aβ) production, aggregation, and clearance, key processes implicated in AD pathogenesis. It also exerts neuroprotective effects, modulates neurotransmitter systems, enhances synaptic plasticity, and stimulates neurogenesis. Furthermore, preclinical and clinical studies have provided evidence supporting the cognition-enhancing effects of agmatine in AD. Therefore, this review article explores the promising role of agmatine in AD pathology and cognitive function. However, several limitations and challenges exist, including the need for large-scale clinical trials, optimal dosing, and treatment duration. Future research should focus on mechanistic investigations, biomarker studies, and personalized medicine approaches to fully understand and optimize the therapeutic potential of agmatine. Augmenting the use of agmatine may offer a novel approach to address the unmet medical need in AD and provide cognitive enhancement and disease modification for individuals affected by this disease.
Collapse
Affiliation(s)
- Raj A Katariya
- Smt. Kishoritai Bhoyar College of Pharmacy, Kamptee, Nagpur, Maharashtra 441002, India
| | - Shivkumar S Sammeta
- Smt. Kishoritai Bhoyar College of Pharmacy, Kamptee, Nagpur, Maharashtra 441002, India
| | - Mayur B Kale
- Smt. Kishoritai Bhoyar College of Pharmacy, Kamptee, Nagpur, Maharashtra 441002, India
| | - Nandkishor R Kotagale
- Government College of Pharmacy, Kathora Naka, VMV Road, Amravati, Maharashtra 444604, India
| | - Milind J Umekar
- Smt. Kishoritai Bhoyar College of Pharmacy, Kamptee, Nagpur, Maharashtra 441002, India
| | - Brijesh G Taksande
- Smt. Kishoritai Bhoyar College of Pharmacy, Kamptee, Nagpur, Maharashtra 441002, India.
| |
Collapse
|
3
|
Lantz MJ, Roberts AM, Delgado DD, Nichols RA. The neuroprotective N-terminal amyloid-β core hexapeptide reverses reactive gliosis and gliotoxicity in Alzheimer's disease pathology models. J Neuroinflammation 2023; 20:129. [PMID: 37245024 DOI: 10.1186/s12974-023-02807-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 05/16/2023] [Indexed: 05/29/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by accumulation of extracellular amyloid beta (Aβ) and intracellular neurofibrillary tangles, leading to chronic activation of astrocytes and microglia and persistent neuroinflammation. Aβ-linked activation of microglia and astrocytes leads to increased intracellular calcium and production of proinflammatory cytokines, impacting the progression of neurodegeneration. An N-terminal Aβ fragment (Aβ1-15) and a shorter hexapeptide core sequence within the N-Aβ fragment (N-Aβcore: Aβ10-15) have previously been shown to protect against Aβ-induced mitochondrial dysfunction, oxidative stress and apoptosis in neurons and rescue synaptic and spatial memory deficits in an APP/PSEN1 mouse model. Here, we hypothesized that the N-Aβ fragment and N-Aβcore are protective against Aβ-induced gliotoxicity, promoting a neuroprotective environment and potentially alleviating the characteristically persistent neuroinflammation present in AD. METHODS We treated ex vivo organotypic brain slice cultures from an aged familial AD mouse model, 5xFAD, with the N-Aβcore and used immunocytochemistry to assess the impact on astrogliosis and microgliosis and alterations in synaptophysin-positive puncta engulfed by microglia. Isolated neuron/glia cultures, mixed glial cultures or a microglial cell line were treated with oligomeric human Aβ at concentrations mimicking the pathogenic concentrations (μM) observed in AD in the absence or presence of the non-toxic N-terminal Aβ fragments. Resultant changes in synaptic density, gliosis, oxidative stress, mitochondrial dysfunction, apoptosis, and the expression and release of proinflammatory markers were then determined. RESULTS We demonstrate that the N-terminal Aβ fragments mitigated the phenotypic switch leading to astrogliosis and microgliosis induced by pathological concentrations of Aβ in mixed glial cultures and organotypic brain slice cultures from the transgenic 5xFAD mouse model, while protecting against Aβ-induced oxidative stress, mitochondrial dysfunction and apoptosis in isolated astrocytes and microglia. Moreover, the addition of the N-Aβcore attenuated the expression and release of proinflammatory mediators in microglial cells activated by Aβ and rescued microglia-mediated loss of synaptic elements induced by pathological levels of Aβ. CONCLUSIONS Together, these findings indicate the protective functions of the N-terminal Aβ fragments extend to reactive gliosis and gliotoxicity induced by Aβ, by preventing or reversing glial reactive states indicative of neuroinflammation and synaptic loss central to AD pathogenesis.
Collapse
Affiliation(s)
- Megan J Lantz
- Department of Cell and Molecular Biology, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Alyssa M Roberts
- Department of Cell and Molecular Biology, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Donovan D Delgado
- Department of Cell and Molecular Biology, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Robert A Nichols
- Department of Cell and Molecular Biology, University of Hawai'i at Mānoa, Honolulu, HI, USA.
| |
Collapse
|
4
|
Whiteaker P, George AA. Discoveries and future significance of research into amyloid-beta/α7-containing nicotinic acetylcholine receptor (nAChR) interactions. Pharmacol Res 2023; 191:106743. [PMID: 37084859 PMCID: PMC10228377 DOI: 10.1016/j.phrs.2023.106743] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/13/2023] [Accepted: 03/21/2023] [Indexed: 04/23/2023]
Abstract
Initiated by findings that Alzheimer's disease is associated with a profound loss of cholinergic markers in human brain, decades of studies have examined the interactions between specific subtypes of nicotinic acetylcholine receptors and amyloid-β [derived from the amyloid precursor protein (APP), which is cleaved to yield variable isoforms of amyloid-β]. We review the evolving understanding of amyloid-β's roles in Alzheimer's disease and pioneering studies that highlighted a role of nicotinic acetylcholine receptors in mediating important aspects of amyloid-β's effects. This review also surveys the current state of research into amyloid-β / nicotinic acetylcholine receptor interactions. The field has reached an exciting point in which common themes are emerging from the wide range of prior research and a range of accessible, relevant model systems are available to drive further progress. We highlight exciting new areas of inquiry and persistent challenges that need to be considered while conducting this research. Studies of amyloid-β and the nicotinic acetylcholine receptor populations that it interacts with provide opportunities for innovative basic and translational scientific breakthroughs related to nicotinic receptor biology, Alzheimer's disease, and cholinergic contributions to cognition more broadly.
Collapse
Affiliation(s)
- Paul Whiteaker
- Virginia Commonwealth University School of Medicine, Department of Pharmacology and Toxicology, VCU Health Sciences Research Building, Box 980613, Richmond, VA 23298-0613, USA
| | - Andrew A George
- Virginia Commonwealth University School of Medicine, Department of Pharmacology and Toxicology, VCU Health Sciences Research Building, Box 980613, Richmond, VA 23298-0613, USA.
| |
Collapse
|
5
|
Reduced SUMOylation of Nrf2 signaling contributes to its inhibition induced by amyloid-β. Neurosci Lett 2023; 799:137118. [PMID: 36764479 DOI: 10.1016/j.neulet.2023.137118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 01/15/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023]
Abstract
Oxidative stress induced by amyloid-β (Aβ) has been considered as one of the important mechanisms in the development of Alzheimer disease (AD). The inhibition of endogenous antioxidant Nrf2 signaling in the brain of AD patients aggravates the oxidative damage, however, the causes of Nrf2 signaling inhibition are unclear. It is reported that smallubiquitin-like modification (SUMOylation) is involved in the process of oxidative injury. To investigate whether and how SUMOylation was involved in the inhibition of Nrf2 signaling pathway induced by Aβ, Aβ intrahippocampal injection rat model and Aβ treated SH-SY5Y cell model were used in the current study. Small interfering RNA and lentivirus transfection were used to intervene SUMOylation, and the level of SUMOylation was assessed by immunoprecipitation. The present in vivo and in vitro studies revealed that SUMOylation levels of Nrf2 and MafF, as well as the overall SUMOylation level were reduced under long-term Aβ insult. Meanwhile, the binding of Nrf2 to MafF was decreased, accompanied by low interaction with antioxidant response element (ARE) area of gene. Down-regulation of SUMO protein exacerbated the Aβ-induced inhibition of Nrf2 signaling pathway, while, enhancement of SUMOylation of Nrf2 and MafF by overexpression of Ubc9 reversed this process. These results imply that reduction in SUMOylation induced by Aβ contributed to the inhibition of Nrf2 signaling, and SUMOylation might be a potential therapeutic target of AD.
Collapse
|
6
|
Zhang Y, Feng J, Ou C, Zhou X, Liao Y. AQP4 mitigates chronic neuropathic pain-induced cognitive impairment in mice. Behav Brain Res 2023; 440:114282. [PMID: 36596395 DOI: 10.1016/j.bbr.2022.114282] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 11/29/2022] [Accepted: 12/30/2022] [Indexed: 01/01/2023]
Abstract
Neuropathic pain is a risk factor for cognitive defects. The ubiquitous expression of AQP4 in astrocytes throughout the central nervous system is altered in the neurodegenerative disease. However, the exact role of AQP4 in cognitive impairment induced by chronic neuropathic pain remains unclear. In this study, we discovered that AQP4 protein and mRNA expression decreased time-dependently in the model of chronic neuropathic pain-induced cognitive disorder. AQP4 overexpression recovered mice from cognitive impairment. Furthermore, the concentration of Aβ1-42 in the serum and hippocampus reduced in mice with AQP4 overexpression adeno-associated virus injection. In conclusion, AQP4 in astrocytes is important in mitigating cognitive impairment caused by chronic neuropathic pain.
Collapse
Affiliation(s)
- Yue Zhang
- Department of Histology, Embryology and Neurobiology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, China; Department of Pain Management, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Jianguo Feng
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China; Laboratory of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Cehua Ou
- Department of Pain Management, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Xue Zhou
- Department of Histology, Embryology and Neurobiology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, China.
| | - Yonghong Liao
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China; Laboratory of Anesthesiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China.
| |
Collapse
|
7
|
Vrabec R, Blunden G, Cahlíková L. Natural Alkaloids as Multi-Target Compounds towards Factors Implicated in Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24054399. [PMID: 36901826 PMCID: PMC10003045 DOI: 10.3390/ijms24054399] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/20/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in elderly people; currently, there is no efficient treatment. Considering the increase in life expectancy worldwide AD rates are predicted to increase enormously, and thus the search for new AD drugs is urgently needed. A great amount of experimental and clinical evidence indicated that AD is a complex disorder characterized by widespread neurodegeneration of the CNS, with major involvement of the cholinergic system, causing progressive cognitive decline and dementia. The current treatment, based on the cholinergic hypothesis, is only symptomatic and mainly involves the restoration of acetylcholine (ACh) levels through the inhibition of acetylcholinesterase (AChE). Since the introduction of the Amaryllidaceae alkaloid galanthamine as an antidementia drug in 2001, alkaloids have been one of the most attractive groups for searching for new AD drugs. The present review aims to comprehensively summarize alkaloids of various origins as multi-target compounds for AD. From this point of view, the most promising compounds seem to be the β-carboline alkaloid harmine and several isoquinoline alkaloids since they can simultaneously inhibit several key enzymes of AD's pathophysiology. However, this topic remains open for further research on detailed mechanisms of action and the synthesis of potentially better semi-synthetic analogues.
Collapse
Affiliation(s)
- Rudolf Vrabec
- Secondary Metabolites of Plants as Potential Drugs Research Group, Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | - Gerald Blunden
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DT, UK
| | - Lucie Cahlíková
- Secondary Metabolites of Plants as Potential Drugs Research Group, Department of Pharmacognosy and Pharmaceutical Botany, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
- Correspondence:
| |
Collapse
|
8
|
Synthesis, biological evaluation and computational investigations of S-benzyl dithiocarbamates as the cholinesterase and monoamine oxidase inhibitors. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
9
|
Yan X, Pan Y, Ji L, Gu J, Hu Y, Xia Y, Li C, Zhou X, Yang D, Yu Y. Multifunctional Metal-Organic Framework as a Versatile Nanoplatform for Aβ Oligomer Imaging and Chemo-Photothermal Treatment in Living Cells. Anal Chem 2021; 93:13823-13834. [PMID: 34609144 DOI: 10.1021/acs.analchem.1c02459] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In view of the close association of β-amyloid oligomers (AβO) with the clinical development of Alzheimer's disease (AD) symptoms, it is urgent to design a promising sensing and therapeutic strategy that can target AβO for preventing or delaying the onset of AD. Herein, a core-shell nanocomposite CeONP-Res-PCM@ZIF-8/polydopamine (PDA) was synthesized through an in situ encapsulated strategy, in which resveratrol (Res), ceria nanoparticles (CeONPs), and PCM (tetradecanol) were embedded into the ZIF-8/PDA matrix via a water-based mild approach. Using the AβO aptamer, the ability of CeONP-Res-PCM@ZIF-8/PDA/Apt as the fluorescent sensing platform for AβO detection and intracellular imaging was demonstrated. The nanocomposite was high in Res loading (27.5%) and could be activated to release the encapsulated Res upon illumination with NIR through PCM regulation. Moreover, due to the synergetic interactions of PDA, CeONPs, and Res in one system, CeONP-Res-PCM@ZIF-8/PDA/Apt nanocomposites exhibited multifunctional effects on inhibiting Aβ aggregation, degrading Aβ fibrils, and alleviating Aβ-induced oxidative stress and neural apoptosis. These therapeutic effects could be enhanced under NIR irradiation by virtue of the excellent photothermal property of PDA. As far as we know, there is no report of using ZIF-8-based materials for simultaneous sensing and therapeutic applications. This work boosted the development of multifunctional nanoagents for biomedical research studies.
Collapse
Affiliation(s)
- Xueyan Yan
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| | - Yixin Pan
- Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Ruijin Hospital, 197 Ruijin Er Road, Shanghai 200025, P. R. China
| | - Liang Ji
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| | - Jinyu Gu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| | - Yuanyuan Hu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| | - Yi Xia
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| | - Chenglin Li
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| | - Xinguang Zhou
- Shenzhen NTEK Testing Technology Co., Ltd., Shenzhen 518000, Guangdong, P. R. China
| | - Dongzhi Yang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| | - Yanyan Yu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Jiangsu 221004, Xuzhou, China
| |
Collapse
|
10
|
Goodman AM, Langner BM, Jackson N, Alex C, McMahon LL. Heightened Hippocampal β-Adrenergic Receptor Function Drives Synaptic Potentiation and Supports Learning and Memory in the TgF344-AD Rat Model during Prodromal Alzheimer's Disease. J Neurosci 2021; 41:5747-5761. [PMID: 33952633 PMCID: PMC8244969 DOI: 10.1523/jneurosci.0119-21.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 02/23/2021] [Accepted: 04/28/2021] [Indexed: 01/27/2023] Open
Abstract
The central noradrenergic (NA) system is critical for the maintenance of attention, behavioral flexibility, spatial navigation, and learning and memory, those cognitive functions lost first in early Alzheimer's disease (AD). In fact, the locus coeruleus (LC), the sole source of norepinephrine (NE) for >90% of the brain, is the first site of pathologic tau accumulation in human AD with axon loss throughout forebrain, including hippocampus. The dentate gyrus is heavily innervated by LC-NA axons, where released NE acts on β-adrenergic receptors (ARs) at excitatory synapses from entorhinal cortex to facilitate long-term synaptic plasticity and memory formation. These synapses experience dysfunction in early AD before cognitive impairment. In the TgF344-AD rat model of AD, degeneration of LC-NA axons in hippocampus recapitulates human AD, providing a preclinical model to investigate synaptic and behavioral consequences. Using immunohistochemistry, Western blot analysis, and brain slice electrophysiology in 6- to 9-month-old wild-type and TgF344-AD rats, we discovered that the loss of LC-NA axons coincides with the heightened β-AR function at medial perforant path-dentate granule cell synapses that is responsible for the increase in LTP magnitude at these synapses. Furthermore, novel object recognition is facilitated in TgF344-AD rats that requires β-ARs, and pharmacological blockade of β-ARs unmasks a deficit in extinction learning only in TgF344-AD rats, indicating a greater reliance on β-ARs in both behaviors. Thus, a compensatory increase in β-AR function during prodromal AD in TgF344-AD rats heightens synaptic plasticity and preserves some forms of learning and memory.SIGNIFICANCE STATEMENT The locus coeruleus (LC), a brain region located in the brainstem which is responsible for attention and arousal, is damaged first by Alzheimer's disease (AD) pathology. The LC sends axons to hippocampus where released norepinephrine (NE) modulates synaptic function required for learning and memory. How degeneration of LC axons and loss of NE in hippocampus in early AD impacts synaptic function and learning and memory is not well understood despite the importance of LC in cognitive function. We used a transgenic AD rat model with LC axon degeneration mimicking human AD and found that heightened function of β-adrenergic receptors in the dentate gyrus increased synaptic plasticity and preserved learning and memory in early stages of the disease.
Collapse
Affiliation(s)
- Anthoni M Goodman
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Bethany M Langner
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Nateka Jackson
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Capri Alex
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| | - Lori L McMahon
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006
| |
Collapse
|
11
|
Gu F, Ji D, Ni H, Chen D. SRY-Box 21 Antisense RNA 1 Knockdown Diminishes Amyloid Beta 25-35-Induced Neuronal Damage by miR-132/PI3K/AKT Pathway. Neurochem Res 2021; 46:2376-2386. [PMID: 34146195 DOI: 10.1007/s11064-021-03373-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 06/04/2021] [Accepted: 06/07/2021] [Indexed: 12/12/2022]
Abstract
Our study aimed to explore the function and mechanism of action of long noncoding RNA (lncRNA) SRY-Box 21 antisense RNA 1 (SOX21-AS1) in amyloid beta25-35 (Aβ25-35)-induced neuronal damage. To induce neuronal damage, neuronal cells and differentiated IMR-32 neuroblastoma cells were challenged by Aβ25-35. SOX21-AS1 and miR-132 quantities were detected by quantitative reverse transcription polymerase chain reaction. Cell damage was evaluated by detecting the changes of cell viability, apoptosis, and oxidative stress. Cell viability was measured using cell counting kit-8. Cell apoptosis was evaluated by flow cytometry and caspase-3 activity. The oxidative stress was analyzed by reactive oxygen species level. The expression of proteins associated with the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was examined by western blot. SOX21-AS1 abundance was up-regulated in Aβ25-35-challenged neuronal cells. Silencing of SOX21-AS1 attenuated Aβ25-35-induced viability reduction and promotion of apoptosis and oxidative stress, suggesting that silencing of SOX21-AS1 repressed Aβ25-35-induced neuronal damage. miR-132 quantity was reduced in Aβ25-35-challenged neuronal cells, and negatively controlled by SOX21-AS1. miR-132 knockdown abolished the effect of SOX21-AS1 silencing on Aβ25-35-induced neuronal damage, indicating that SOX21-AS1 controls Aβ25-35-induced neuronal damage via regulating miR-132. The PI3K/AKT signaling was repressed in Aβ25-35-challenged cells, but this effect was counteracted upon overexpression of miR-132. In conclusion, SOX21-AS1 knockdown mitigated Aβ25-35-dependent neuronal cell damage by promoting miR-132/PI3K/AKT pathway.
Collapse
Affiliation(s)
- Fengming Gu
- Department of Intensive Care Unit, The Affiliated Huai'an Hospital of Xuzhou Medical University, The Second People's Hospital of Huai'an, Huai'an, 223002, China
| | - Daofei Ji
- Department of Neurosurgery, The Second Affiliated Hospital of Xuzhou Medical University, Xuzhou, 221006, China
| | - Hongzao Ni
- Department of Neurosurgery, The Affiliated Huai'an Hospital of Xuzhou Medical University, The Second People's Hospital of Huai'an, Huai'an, 223002, China
| | - Depeng Chen
- Department of Intensive Care Unit, People's Hospital of Huai'an Hongze District, 102 Dongfeng Road, Huai'an, 223100, China.
| |
Collapse
|
12
|
Zolotarev YA, Mitkevich VA, Shram SI, Adzhubei AA, Tolstova AP, Talibov OB, Dadayan AK, Myasoyedov NF, Makarov AA, Kozin SA. Pharmacokinetics and Molecular Modeling Indicate nAChRα4-Derived Peptide HAEE Goes through the Blood-Brain Barrier. Biomolecules 2021; 11:biom11060909. [PMID: 34207317 PMCID: PMC8234734 DOI: 10.3390/biom11060909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 12/24/2022] Open
Abstract
One of the treatment strategies for Alzheimer's disease (AD) is based on the use of pharmacological agents capable of binding to beta-amyloid (Aβ) and blocking its aggregation in the brain. Previously, we found that intravenous administration of the synthetic tetrapeptide Acetyl-His-Ala-Glu-Glu-Amide (HAEE), which is an analogue of the 35-38 region of the α4 subunit of α4β2 nicotinic acetylcholine receptor and specifically binds to the 11-14 site of Aβ, reduced the development of cerebral amyloidogenesis in a mouse model of AD. In the current study on three types of laboratory animals, we determined the biodistribution and tissue localization patterns of HAEE peptide after single intravenous bolus administration. The pharmacokinetic parameters of HAEE were established using uniformly tritium-labeled HAEE. Pharmacokinetic data provided evidence that HAEE goes through the blood-brain barrier. Based on molecular modeling, a role of LRP1 in receptor-mediated transcytosis of HAEE was proposed. Altogether, the results obtained indicate that the anti-amyloid effect of HAEE, previously found in a mouse model of AD, most likely occurs due to its interaction with Aβ species directly in the brain.
Collapse
Affiliation(s)
- Yurii A. Zolotarev
- Laboratory of Protein Conformational Polymorphism in Health and Disease, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.A.Z.); (V.A.M.); (A.A.A.); (A.P.T.); (A.A.M.)
- Department of Physiologically Active Substances Chemistry, Institute of Molecular Genetics of National Research Center «Kurchatov Institute», 123182 Moscow, Russia; (S.I.S.); (A.K.D.); (N.F.M.)
| | - Vladimir A. Mitkevich
- Laboratory of Protein Conformational Polymorphism in Health and Disease, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.A.Z.); (V.A.M.); (A.A.A.); (A.P.T.); (A.A.M.)
| | - Stanislav I. Shram
- Department of Physiologically Active Substances Chemistry, Institute of Molecular Genetics of National Research Center «Kurchatov Institute», 123182 Moscow, Russia; (S.I.S.); (A.K.D.); (N.F.M.)
| | - Alexei A. Adzhubei
- Laboratory of Protein Conformational Polymorphism in Health and Disease, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.A.Z.); (V.A.M.); (A.A.A.); (A.P.T.); (A.A.M.)
| | - Anna P. Tolstova
- Laboratory of Protein Conformational Polymorphism in Health and Disease, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.A.Z.); (V.A.M.); (A.A.A.); (A.P.T.); (A.A.M.)
| | - Oleg B. Talibov
- Department of Clinical Pharmacology, Faculty of Common Medicine, Evdokimov Moscow State University of Medicine and Dentistry, 127473 Moscow, Russia;
| | - Alexander K. Dadayan
- Department of Physiologically Active Substances Chemistry, Institute of Molecular Genetics of National Research Center «Kurchatov Institute», 123182 Moscow, Russia; (S.I.S.); (A.K.D.); (N.F.M.)
| | - Nikolai F. Myasoyedov
- Department of Physiologically Active Substances Chemistry, Institute of Molecular Genetics of National Research Center «Kurchatov Institute», 123182 Moscow, Russia; (S.I.S.); (A.K.D.); (N.F.M.)
| | - Alexander A. Makarov
- Laboratory of Protein Conformational Polymorphism in Health and Disease, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.A.Z.); (V.A.M.); (A.A.A.); (A.P.T.); (A.A.M.)
| | - Sergey A. Kozin
- Laboratory of Protein Conformational Polymorphism in Health and Disease, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia; (Y.A.Z.); (V.A.M.); (A.A.A.); (A.P.T.); (A.A.M.)
- Correspondence: ; Tel.: +7-499-135-98-24
| |
Collapse
|
13
|
Forest KH, Taketa R, Arora K, Todorovic C, Nichols RA. The Neuroprotective Beta Amyloid Hexapeptide Core Reverses Deficits in Synaptic Plasticity in the 5xFAD APP/PS1 Mouse Model. Front Mol Neurosci 2021; 14:576038. [PMID: 33912008 PMCID: PMC8075567 DOI: 10.3389/fnmol.2021.576038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 03/11/2021] [Indexed: 11/16/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in the aging population. Evidence implicates elevated soluble oligomeric Aβ as one of the primary triggers during the prodromic phase leading to AD, effected largely via hyperphosphorylation of the microtubule-associated protein tau. At low, physiological levels (pM-nM), however, oligomeric Aβ has been found to regulate synaptic plasticity as a neuromodulator. Through mutational analysis, we found a core hexapeptide sequence within the N-terminal domain of Aβ (N-Aβcore) accounting for its physiological activity, and subsequently found that the N-Aβcore peptide is neuroprotective. Here, we characterized the neuroprotective potential of the N-Aβcore against dysfunction of synaptic plasticity assessed in ex vivo hippocampal slices from 5xFAD APP/PS1 mice, specifically hippocampal long-term potentiation (LTP) and long-term depression (LTD). The N-Aβcore was shown to reverse impairment in synaptic plasticity in hippocampal slices from 5xFAD APP/PS1 model mice, both for LTP and LTD. The reversal by the N-Aβcore correlated with alleviation of downregulation of hippocampal AMPA-type glutamate receptors in preparations from 5xFAD mice. The action of the N-Aβcore depended upon a critical di-histidine sequence and involved the phosphoinositide-3 (PI3) kinase pathway via mTOR (mammalian target of rapamycin). Together, the present findings indicate that the non-toxic N-Aβcore hexapeptide is not only neuroprotective at the cellular level but is able to reverse synaptic dysfunction in AD-like models, specifically alterations in synaptic plasticity.
Collapse
Affiliation(s)
| | | | | | | | - Robert A. Nichols
- Department of Cell & Molecular Biology, John A. Burns School of Medicine, University of Hawai‘i at Mānoa, Honolulu, HI, United States
| |
Collapse
|
14
|
Li H, Lei T, Zhang J, Yan Y, Wang N, Song C, Li C, Sun M, Li J, Guo Y, Yang J, Kang T. Longan (Dimocarpus longan Lour.) Aril ameliorates cognitive impairment in AD mice induced by combination of D-gal/AlCl 3 and an irregular diet via RAS/MEK/ERK signaling pathway. JOURNAL OF ETHNOPHARMACOLOGY 2021; 267:113612. [PMID: 33249246 DOI: 10.1016/j.jep.2020.113612] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE According to the theory of traditional Chinese medicine (TCM), Alzheimer's disease (AD) is identified as "forgetfulness" or "dementia", and it can be caused by spleen deficiency. Longan Aril (the aril of Dimocarpus longan Lour., LA) is a kind of Chinese medicine, and it can improve intelligence attributed to entering the spleen-meridian. This study aimed to explore the therapeutic effects of LA on AD mice with spleen deficiency, and to understand anti-AD mechanism of LA. MATERIAL AND METHODS A mouse model of AD with spleen deficiency was established by D-gal (140 mg/kg, intraperitoneal injection) and AlCl3 (20 mg/kg, intragastrical administration) in combination with an irregular diet for 60 days, in which mice in LA group were daily given LA (0.5, 1.0 or 2.0 g/kg). The anti-AD effects of LA were evaluated by the Morris water maze, enzyme-linked immunosorbent assay (ELISA), hematoxylin and eosin (H&E), Nissl, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. The anti-AD mechanism of LA was studied by using metabolomics, and the expressions of RAS/MEK/extracellular signal-regulated kinase (ERK) signaling pathway-related proteins were detected by Western blotting. RESULTS LA improved learning and memory abilities, superoxide dismutase (SOD) level, and form and number of Nissl bodies, while reduced the levels of Aβ42, phosphorylated-tau (p-tau), reactive oxygen species (ROS), malondialdehyde (MDA), monoamine oxidase-B (MAO-B), histological injury, and apoptosis rate in AD group (P < 0.05, P < 0.01 or P < 0.001). The anti-AD mechanism of LA may be related to RAS/MEK/ERK and other signaling pathways, in which the expressions of RAS/MEK/ERK signaling pathway-related proteins significantly reduced (P < 0.05 or P < 0.01). CONCLUSIONS LA could improve the cognitive ability and reduce the pathologic impairment in AD mice, which might be partly mediated via inhibition of RAS/MEK/ERK singling pathway.
Collapse
Affiliation(s)
- Hongyan Li
- The Ministry of National Education Key Lab for TCM Visceral Manifestations Theory and Application, Liaoning University of Traditional Chinese Medicine, Shenyang, 110032, China; Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China.
| | - Tianrong Lei
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Jianghua Zhang
- College of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, 116034, China
| | - Yuhui Yan
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Nan Wang
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Cheng Song
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Chang Li
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Mingyu Sun
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Jinyu Li
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Yuxin Guo
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Jingxian Yang
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| | - Tingguo Kang
- Pharmaceutical College, Liaoning University of Traditional Chinese Medicine, Dalian, 116600, China
| |
Collapse
|
15
|
SQSTM1/ p62 oligomerization contributes to Aβ-induced inhibition of Nrf2 signaling. Neurobiol Aging 2020; 98:10-20. [PMID: 33227565 DOI: 10.1016/j.neurobiolaging.2020.05.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/13/2020] [Accepted: 05/10/2020] [Indexed: 12/15/2022]
Abstract
SQSTM1/p62, also known as sequestosome 1 (SQSTM1) or p62, is an intracellular protein induced by stress and functions as an adaptor molecule in diverse cellular processes. Oxidative damage induced by overproduction of amyloid-β (Aβ) and the impairment of endogenous antioxidant Nrf2 signaling have been documented in the brains of Alzheimer's disease (AD) patients. The causes of the inactivation of Nrf2 signaling under Aβ-induced oxidative stress are unclear, and p62 might be involved in this process. In this study, APP/PS1 transgenic mice, Aβ intrahippocampal injection rat model, and SH-SY5Y cells were used to reveal that the alterations in the oligomeric state of p62 participated in the regulation of Nrf2 signaling under Aβ insult. The present in vivo and in vitro studies revealed that short-term treatment of Aβ activated Nrf2 signaling, while long-term Aβ treatment inhibited it through either canonical or noncanonical Nrf2 activation pathway. p62 oligomerization was largely attenuated under long-term Aβ treatment. The reduction of p62 oligomerization weakened p62 sequestration to Keap1, leading to Nrf2 signaling inhibition. Our findings provide a better understanding of p62-mediated modulation on Nrf2 activity and highlight a potential therapeutic target of p62 in AD.
Collapse
|
16
|
Tan X, Liang Z, Li Y, Zhi Y, Yi L, Bai S, Forest KH, Nichols RA, Dong Y, Li QX. Isoorientin, a GSK-3β inhibitor, rescues synaptic dysfunction, spatial memory deficits and attenuates pathological progression in APP/PS1 model mice. Behav Brain Res 2020; 398:112968. [PMID: 33069740 DOI: 10.1016/j.bbr.2020.112968] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 09/13/2020] [Accepted: 10/10/2020] [Indexed: 02/07/2023]
Abstract
β-Amyloid (Aβ) elevation, tau hyperphosphorylation, and neuroinflammation are major hallmarks of Alzheimer's disease (AD). Glycogen synthase kinase-3β (GSK-3β) is a key protein kinase implicated in the pathogenesis of AD. Blockade of GSK-3β is an attractive therapeutic strategy for AD. Isoorientin, a 6-C-glycosylflavone, was previously shown to be a highly selective inhibitor of GSK-3β, while exerting neuroprotective effects in neuronal models of AD. In the present study, we evaluated the in vivo effects of isoorientin on GSK-3β, tau phosphorylation, Aβ deposition, neuroinflammatory response, long-term potentiation, and spatial memory in amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice using biochemical, electrophysiological, and behavioral tests. Chronic oral administration of isoorientin to APP/PS1 mice at 8 months of age attenuated multiple AD pathogenic hallmarks in the brains, including GSK-3β overactivation, tau hyperphosphorylation, Aβ deposition, and neuroinflammation. For neuroinflammation, isoorientin treatment reduced the number of activated microglia associated with Aβ-positive plaques, and in parallel reduced the levels of pro-inflammatory factors in the brains of APP/PS1 mice. Strikingly, isoorientin reversed deficits in synaptic long-term potentiation and spatial memory relevant to cognitive functions. Together, the findings suggest that isoorientin is a brain neuroprotector and may be a promising drug lead for treatment of AD and related neurodegenerative disorders.
Collapse
Affiliation(s)
- Xiaoqin Tan
- Department of Immunology, Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510405, China; Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, United States
| | - Zhibin Liang
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, United States
| | - Yingui Li
- Department of Immunology, Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Yingkun Zhi
- Department of Immunology, Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Lang Yi
- Department of Immunology, Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Shasha Bai
- Department of Immunology, Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Kelly H Forest
- Department of Cell and Molecular Biology, John A. Burn School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, HI 96813, United States
| | - Robert A Nichols
- Department of Cell and Molecular Biology, John A. Burn School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Honolulu, HI 96813, United States
| | - Yan Dong
- Department of Immunology, Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou 510405, China.
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, United States.
| |
Collapse
|
17
|
Tetrapeptide Ac-HAEE-NH 2 Protects α4β2 nAChR from Inhibition by Aβ. Int J Mol Sci 2020; 21:ijms21176272. [PMID: 32872553 PMCID: PMC7504039 DOI: 10.3390/ijms21176272] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 12/25/2022] Open
Abstract
The cholinergic deficit in Alzheimer’s disease (AD) may arise from selective loss of cholinergic neurons caused by the binding of Aβ peptide to nicotinic acetylcholine receptors (nAChRs). Thus, compounds preventing such an interaction are needed to address the cholinergic dysfunction. Recent findings suggest that the 11EVHH14 site in Aβ peptide mediates its interaction with α4β2 nAChR. This site contains several charged amino acid residues, hence we hypothesized that the formation of Aβ-α4β2 nAChR complex is based on the interaction of 11EVHH14 with its charge-complementary counterpart in α4β2 nAChR. Indeed, we discovered a 35HAEE38 site in α4β2 nAChR, which is charge-complementary to 11EVHH14, and molecular modeling showed that a stable Aβ42-α4β2 nAChR complex could be formed via the 11EVHH14:35HAEE38 interface. Using surface plasmon resonance and bioinformatics approaches, we further showed that a corresponding tetrapeptide Ac-HAEE-NH2 can bind to Aβ via 11EVHH14 site. Finally, using two-electrode voltage clamp in Xenopus laevis oocytes, we showed that Ac-HAEE-NH2 tetrapeptide completely abolishes the Aβ42-induced inhibition of α4β2 nAChR. Thus, we suggest that 35HAEE38 is a potential binding site for Aβ on α4β2 nAChR and Ac-HAEE-NH2 tetrapeptide corresponding to this site is a potential therapeutic for the treatment of α4β2 nAChR-dependent cholinergic dysfunction in AD.
Collapse
|